This project is aimed at obtaining methods such that appropriate therapy drugs (or procedures) may be rationally applied to the patient with autoimmune hemolytic anemia. The type and quantity of immunoglobulins and complement components present on erythrocytes from patients with autoimmune hemolytic anemia will be determined by radio immune inhibition studies. This technique is capable of reproducible measurements of proteins at the nanogram level. This will permit estimations of the amount of immunoglobulin or complement component per red cell. The relationships between these parameters and phagocytosis of erythrocytes by reticuloendothelial cells, will be studied using peripheral blood monocyte as a model in in vitro studies. The interplay between amount and type of erythrocyte coat, monocyte function, red cell survival in vivo, and clinical manifestations of disease will be determined. The modification of these components by current modes of therapy will be explored.